At the height of World War I, 2,000 Cambodian volunteers were sent to the fields of France to support their colonial rulers. Many did not return.

March 1916. As artillery shells pounded the battlefields of eastern France, Sen Sak, a Cambodian widow, pleaded with the head of the French administration in Phnom Penh to allow her only child, Sen Sam, to leave the army before he was sent to fight in Europe’s distant war.

Without teenage Sam, her only close relative after the successive deaths of her husband and daughter, Sak wrote to Resident Superior François Baudoin that she would be “abandoned and miserable”.

“I pray and beg you, M. Resident Superior, to accord me this grace,” she wrote. “I can already feel my heart breaking.”

After travelling to the capital from her Kampong Chhnang village to beg her son not to go, he had reversed his decision, she claimed.

Scribbled on the same letter – buried in Cambodia’s National Archives – is Baudoin’s reply. Faded to the point of illegibility, it is unclear if he accepted her request. It is also unknown if Sam deserted anyway or dutifully donned his uniform and boarded a steamer to the port of Marseille like approximately 2,000 other Cambodians eventually did by war’s end in 1918.

One hundred years ago this month, at the outbreak of the First World War, and nearly two years before the heartbroken mother put pen to paper, the French authorities in Indochina offered battalions of “native soldiers” for the war effort in Europe.

They were rejected. The war, they were told, would be over by Christmas.

But as historian John Tully notes in Cambodia Under The Tricolour, “By 1916, the euphoria had evaporated and the enormous casualties suffered in the trenches (equal to the population of Poitiers every week) could not long be replaced from [France’s] metropolitan population of 40 million.”

France, like Britain, turned to its empire.

It was initially thought that hundreds of thousands could be raised in Indochina, but the figure was later limited to 50,000, according to Tully. Of that, the overwhelming majority were Vietnamese, but Cambodia was asked to provide 2,500 tirailleurs (light infantry) and workers to serve in the trenches, garrisons and factories of France.

The call was strongly backed by the Royal Palace, with then-King Sisowath serving as president of a committee in charge of organising recruitment.

“The members of the royal family, ministers, government officials of all ranks, all the Cambodian people and myself, have for France a love and a devotion without bounds,” he proclaimed.

An intense propaganda campaign began. Notices were posted in every village; high-ranking French officials and royalty went out on recruiting drives.

“The monks were put to work contributing to the ordinary recruitment drives, while the King himself would go to the districts promising honourific distinctions and jobs in the administration and at the Royal Palace to those who joined,” French historian Alain Forest writes.

But according to Forest, after three months, only 2,295 people had volunteered to serve as soldiers, of which 508 were sent home after it became apparent they had been coerced to join by local authorities. Of those remaining, 1,008 were deemed appropriate for military service. Of that number, 20 died during training and 340 more deserted.

As he reported a batch of just 28 new recruits from Kampong Cham and Kratie provinces in May 1916, War Minister Chakrey Ponn attributed slow recruitment “not to a hostile sentiment towards the protectorate, but to the fact that Cambodians are very attached to their homes and do not like to go abroad.

“Having a far from belligerent character, they content themselves with their farms.”

Despite Ponn’s assurances, the recruitment drive, in fact, coincided with peasant protests against French taxation now known as the “1916 Affair”. In this atmosphere, anti-recruitment propaganda also flourished, contributing to desertions and slowing enlistment.

Nevertheless, on May 1, 1916, the first battalion of Cambodian soldiers – the 20th Indochinese – proudly set sail for France, waved off by large crowds.

Arriving in Marseille, they boarded trains to barracks further east, in Fréjus, for basic training.

While the largely uneducated volunteers may have had trouble adjusting, small concessions had been made to ease the transition. The men arriving dined on dried fish, vermicelli and even prahok, according to Tully.

They were also welcomed by locals bearing gifts of flowers and wine, some soldiers later said, and “amused themselves by sending ‘obscene’ postcards to friends and relatives” and apparently even charming pretty French girls.

But early contact with working locals, particularly in the factories, was already worrying the colonial administration.

On May 27, 1916, Nguyen Van Vinh, a high-ranking Vietnamese colonial administrator posted with the Indochinese volunteers, noted that such contact could see them “lose their native quality of docility” when they return home.

“Outside of the workshops and barracks, the men have gotten used to a certain liberty which they may retain as they come back to Indochina,” he wrote.

Although Vinh’s fears may have been overblown, at least two veterans – Pach Chhoeun and Kim Tith – later became prominent nationalists and figures in the independence movement.

While Baudoin and other French colonial officials initially lamented the lack of military prowess they perceived in Cambodians, the volunteers were ultimately praised for their bravery on the battlefield.

Many served as garrison troops in France and Macedonia. But others saw action in Vietnamese-Cambodian frontline units on the Western Front – at the ferocious Battle of Verdun, in the Vosges mountains of Alsace and the Chemins des Dames in Aisne. Cambodians also fought on the Balkans front.

Indochinese troops were said to be especially brave during patrols towards enemy trenches, Tully writes, although given that tirailleurs were often used in this manner, “the unavoidable conclusion is that they were seen as being more expendable than Europeans.”

An October 1918 letter from Baudoin to the family of a volunteer tirailleur named Nuon, from Prey Veng province, killed on July 28 on the Alsace front and awarded the Croix de Guerre, cites his courage.

“A brave tirailleur, who stayed brave under a violent bombardment. Killed in the accomplishment of his duty.”

Nuon’s family, like those of most who volunteered, were poor.

“The mother, 47, farms three little rice paddies which they own. These people live in misery, so I have sent [them] the sum of 30 piastres,” a French official in Prey Veng wrote to Baudoin.

Maurice Rives, of the National Association of Friends of Indochina, writes that the French infantry, or poilus, considered their Asian comrades “unaffected by the artillery shells, serious, cold, with nerves of steel”.

While the number of Cambodians who died serving France in the war is unknown, some commanders estimated that 115,000 of a total 545,000 colonial soldiers died in battle – a 20 per cent death rate, compared to 15 per cent for European troops.

Their names have long been forgotten and the stories of Cambodia’s involvement in the Great War are now relegated to the pages of a few history books and the shelves of colonial archives. But last month, a small group of Cambodian youth, officials and soldiers joined a Bastille Day march in Paris to commemorate the centenary of the war.

While the war was credited with blood-bonding the friendship between French and Khmer, and Cambodians undoubtedly held their own on the battlefields, some believe it was less patriotic fervour for the protectorate, and more a spirit of adventure, that drew young Khmers to serve.

Huy Kanthoul, who interviewed veterans and later became prime minister in 1951, puts it down to the determined curiosity of men who had heard so much, for so long, about the land from which those who ran their country had come.

“They wished to travel, to cross the seas, see France,” he wrote in his unpublished memoirs.

“The marvels of which they had heard extolled so much.”